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📦 npm

GHSA-5rwj-j5m3-3chj

HIGH

Missing Release of Memory after Effective Lifetime in detect-character-encoding

Also known asCVE-2021-39176
Published
Sep 1, 2021
Updated
Mar 13, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
1 known

EPSS Exploitation Probability

via FIRST.org ↗
1.8%probability of exploitation in next 30 days
Lower Risk76th percentile+1.22%
0.11%0.85%1.59%2.33%0.6%1.8%Dec 25Apr 26Jun 26

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

Weekly download volume for affected packages — a proxy for how broadly this vulnerability is deployed.

detect-character-encodingnpm
1Kdownloads / week

Description

Impact

In detect-character-encoding v0.3.0 and earlier, allocated memory is not released.

Patches

The problem has been patched in detect-character-encoding v0.3.1.

CVSS score

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/RL:O/RC:C

Base Score: 7.5 (High) Temporal Score: 7.2 (High)

Since detect-character-encoding is a library, the scoring is based on the “reasonable worst-case implementation scenario”, namely, using detect-character-encoding in a program accessible over the internet which becomes unavailable when running out of memory. Depending on your specific implementation, the vulnerability’s severity in your program may be different.

Proof of concept

const express = require("express");
const detectCharacterEncoding = require("detect-character-encoding");

const app = express();

app.get("/", (req, res) => {
  detectCharacterEncoding(Buffer.from("foo"));

  res.end();
});

app.listen(3000);

hey -n 1000000 http://localhost:3000 (hey) causes the Node.js process to consume more and more memory.

References

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
📦npmdetect-character-encodingall versions0.3.1
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for detect-character-encoding. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update detect-character-encoding to 0.3.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-5rwj-j5m3-3chj is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-5rwj-j5m3-3chj is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-5rwj-j5m3-3chj. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact In detect-character-encoding v0.3.0 and earlier, allocated memory is not released. ### Patches The problem has been patched in [detect-character-encoding v0.3.1](https://github.com/sonicdoe/detect-character-encoding/releases/tag/v0.3.1). ### CVSS score [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/RL:O/RC:C](https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/RL:O/RC:C) Base Score: 7.5 (High) Temporal Score: 7.2 (High) Since detect-character-encoding is a library, the scoring is based on the “[reasonable worst-case implementation scenario](h
O3 Security · Impact-Aware SCA

Is GHSA-5rwj-j5m3-3chj in your dependencies?

O3 detects GHSA-5rwj-j5m3-3chj across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.